Enabling device-to-device discovery

ABSTRACT

Methods, systems, and devices are describe for signaling protocols for device-to-device discovery operations in a wireless communication system. A user equipment (UE) may be communicating with a serving base station using a first frequency in a first frequency band. The UE may transmit, to the serving base station, information associated with performing a discovery scan procedure on a second frequency in a second frequency band during a discovery scan interval. The first frequency may be different from the second frequency. The UE may identify a capability to skip one or more downlink transmissions from the serving base station during the discovery scan interval.

CROSS REFERENCES

The present Application for Patent claims priority to U.S. ProvisionalPatent Application No. 62/142,969 by Patil et al., entitled “ENABLINGDEVICE-TO-DEVICE DISCOVERY,” filed Apr. 3, 2015, assigned to theassignee hereof, and expressly incorporated by reference herein.

BACKGROUND

Field of the Disclosure

The present disclosure, for example, relates to wireless communicationsystems, and more particularly to enabling a device-to-device discoveryprocedure.

Description of Related Art

Wireless communication systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be multiple-accesssystems capable of supporting communication with multiple users bysharing the available system resources (e.g., time, frequency, andpower). Examples of such multiple-access systems include code-divisionmultiple access (CDMA) systems, time-division multiple access (TDMA)systems, frequency-division multiple access (FDMA) systems, andorthogonal frequency-division multiple access (OFDMA) systems.

By way of example, a wireless multiple-access communication system mayinclude a number of base stations, each simultaneously supportingcommunication for multiple communication devices, otherwise known asuser equipments (UEs). A base station may communicate with UEs ondownlink channels (e.g., for transmissions from a base station to a UE)and uplink channels (e.g., for transmissions from a UE to a basestation).

Typically, UEs engage in wireless communication by communicating with abase station of a wireless communications system. However, UEs may alsoparticipate in direct D2D or ProSe wireless communications. D2Ddiscovery allows UEs that are within range of each other to communicatedirectly with each other instead of communicating through a basestation. One UE may broadcast a D2D discovery announcement, such as aDirect Peer-Discovery Signal in a Long Term Evolution (LTE) system,which may then be received by the neighboring UEs in the proximity thatare monitoring such discovery communications. A monitoring UE mayreceive the D2D discovery announcement and perform an associationprocedure to authenticate and establish communications with theannouncing UE. Such discovery procedures, however, become problematicwhen the announcing UE and the monitoring UE are operating on differentfrequencies and, in some situations, via different carriers. Forexample, a monitoring UE that is camped on and communicating with aserving base station may need to tune to the frequency of the announcingUE to detect the discovery signal, which may disrupt communications withthe serving base station.

SUMMARY

The described features generally relate to one or more improved methods,systems, devices, or apparatuses that enable D2D discovery procedures.Generally, the improved methods may provide for a monitoring UE toperform a discovery procedure with an announcing UE while in an activecommunication session with a serving base station. The announcing UE maycommunicate using a different frequency than the frequency used forcommunications with the monitoring UE and the serving base station,which may result in the monitoring UE skipping certain downlinktransmissions during the discovery scan procedure. For example, themonitoring UE may be in an active communication session with the servingbase station using a first frequency in a first frequency band. Themonitoring UE may send to the serving base station informationassociated with performing a discovery scan procedure on a secondfrequency in a second frequency band during a discovery scan interval.The first and second frequencies may be different. The monitoring UE mayidentify (autonomously and/or based on information received from theserving base station) a capability to skip at least a portion ofdownlink transmissions from the serving base station during thediscovery scan interval. Accordingly, the monitoring UE may be able toinform the serving base station about an intention, desire, etc., toperform an inter-frequency and, in some cases, inter-carrier, discoveryscan that may result in skipping certain downlink transmissions from theserving base station.

In a first illustrative set of examples, a method for wirelesscommunication at a user equipment (UE) is provided. The method mayinclude: communicating with a serving base station using a firstfrequency in a first frequency band; transmitting, to the serving basestation, information associated with performing a discovery scanprocedure on a second frequency in a second frequency band during adiscovery scan interval, the second frequency being different from thefirst frequency; and identifying a capability to skip one or moredownlink transmissions from the serving base station during thediscovery scan interval.

In some aspects, the method may include tuning to the second frequencyduring the discovery scan interval; and skipping the one or moredownlink transmissions from the serving base station during thediscovery scan interval. The method may include receiving a responsefrom the serving base station; and skipping at least a portion of theone or more downlink transmissions from the serving base station duringthe discovery scan interval based at least in part on the receivedresponse. The response may include permission to skip the at least aportion of the one or more downlink transmissions from the serving basestation during the discovery scan interval.

In some aspects, the method may include skipping a first portion of theone or more downlink transmissions from the serving base station duringthe discovery scan interval based at least in part on the receivedresponse; and receiving a second portion of the one or more downlinktransmissions from the serving base station during the discovery scaninterval based at least in part on the received response. The responsemay include a bitmap associated with the one or more downlinktransmissions from the serving base station, the bitmap identifying afirst portion of the one or more downlink transmissions the UE isallowed to skip and a second portion the one or more downlinktransmissions the UE is not allowed to skip.

In some aspects, the method may include sending timing informationassociated with the discovery scan interval to the serving base station.The timing information may include an identification of one or moresub-frames where the UE skips the one or more downlink transmissionsfrom the serving base station. The method may include selecting the oneor more sub-frames based on a timing difference between the serving basestation and another device transmitting the discovery signal associatedwith the discovery scan procedure. The method may include determining atiming parameter associated with tuning to and tuning away from thesecond frequency band; and selecting the one or more sub-frames toaccount for the timing parameter.

In some aspects, the serving base station may be associated with a firstnetwork and the discovery scan procedure may be associated with a secondnetwork, the first network being different from the second network. Thediscovery scan procedure may be a device-to-device discovery procedure.

In a second illustrative set of examples, an apparatus for wirelesscommunication is provided. The apparatus may include: a processor;memory in electronic communication with the processor; and instructionsstored in the memory, the instructions being executable by the processorto: communicate with a serving base station using a first frequency in afirst frequency band; transmit, to the serving base station, informationassociated with performing a discovery scan procedure on a secondfrequency in a second frequency band during a discovery scan interval,the second frequency being different from the first frequency; andidentify a capability to skip one or more downlink transmissions fromthe serving base station during the discovery scan interval.

In some aspects, the apparatus may include instructions executable bythe processor to: tune to the second frequency during the discovery scaninterval; and skip the one or more downlink transmissions from theserving base station during the discovery scan interval. The apparatusmay include instructions executable by the processor to: receive aresponse from the serving base station; and skip at least a portion ofthe one or more downlink transmissions from the serving base stationduring the discovery scan interval based at least in part on thereceived response. The response may include permission to skip the atleast a portion of the one or more downlink transmissions from theserving base station during the discovery scan interval.

In some aspects, the apparatus may include instructions executable bythe processor to: skip a first portion of the one or more downlinktransmissions from the serving base station during the discovery scaninterval based at least in part on the received response; and receive asecond portion of the one or more downlink transmissions from theserving base station during the discovery scan interval based at leastin part on the received response. The response may include a bitmapassociated with the one or more downlink transmissions from the servingbase station, the bitmap identifying a first portion of the one or moredownlink transmissions the UE is allowed to skip and a second portionthe one or more downlink transmissions the UE is not allowed to skip.

In some aspects, the apparatus may include instructions executable bythe processor to send timing information associated with the discoveryscan interval to the serving base station. The timing information mayinclude an identification of one or more sub-frames where the UE skipsthe one or more downlink transmissions from the serving base station.The apparatus may include instructions executable by the processor toselect the one or more sub-frames based on a timing difference betweenthe serving base station and another device transmitting the discoverysignal associated with the discovery scan procedure. The apparatus mayinclude instructions executable by the processor to: determine a timingparameter associated with tuning to and tuning away from the secondfrequency band; and select the one or more sub-frames to account for thetiming parameter.

In some aspects, the serving base station may be associated with a firstnetwork and the discovery scan procedure may be associated with a secondnetwork, the first network being different from the second network. Thediscovery scan procedure may be a device-to-device discovery procedure.

In a third illustrative set of examples, a method for wirelesscommunication at a serving base station is provided. The method mayinclude: communicating with a user equipment (UE) using a firstfrequency in a first frequency band; receiving, from the UE, informationassociated with the UE performing a discovery scan procedure on a secondfrequency in a second frequency band during a discovery scan interval,the second frequency being different from the first frequency; andsending a response to the UE indicating whether the UE is allowed toskip one or more downlink transmissions during the discovery scaninterval.

In some aspects, the method may include receiving a capability messagefrom the UE indicating the UE is capable of skipping the one or moredownlink transmissions during the discovery scan interval. The responsemay identify a first portion of the one or more downlink transmissionsthe UE is allowed to skip during the discovery scan interval. Theresponse may identify a second portion of the one or more downlinktransmissions the UE is not allowed to skip during the discovery scaninterval. The method may include receiving timing information associatedwith the discovery scan interval from the UE.

In a fourth illustrative set of examples, an apparatus for wirelesscommunication is provided. The apparatus may include: a processor;memory in electronic communication with the processor; and instructionsstored in the memory, the instructions being executable by the processorto: communicate with a user equipment (UE) using a first frequency in afirst frequency band; receive, from the UE, information associated withthe UE performing a discovery scan procedure on a second frequency in asecond frequency band during a discovery scan interval, the secondfrequency being different from the first frequency; and send a responseto the UE indicating whether the UE is allowed to skip one or moredownlink transmissions during the discovery scan interval.

In some aspects, the apparatus may include instructions executable bythe processor to receive a capability message from the UE indicating theUE is capable of skipping the one or more downlink transmissions duringthe discovery scan interval. The response may identify a first portionof the one or more downlink transmissions the UE is allowed to skipduring the discovery scan interval. The response may identify a secondportion of the one or more downlink transmissions the UE is not allowedto skip during the discovery scan interval. The apparatus may includeinstructions executable by the processor to receive timing informationassociated with the discovery scan interval from the UE.

The foregoing has outlined rather broadly the features and technicaladvantages of examples according to the disclosure in order that thedetailed description that follows may be better understood. Additionalfeatures and advantages will be described hereinafter. The conceptionand specific examples disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present disclosure. Such equivalent constructions do notdepart from the scope of the appended claims. Characteristics of theconcepts disclosed herein, both their organization and method ofoperation, together with associated advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. Each of the figures is provided for the purpose ofillustration and description only, and not as a definition of the limitsof the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the following drawings. In theappended figures, similar components or features may have the samereference label. Further, various components of the same type may bedistinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If only the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

FIG. 1 shows a block diagram of a wireless communication system, inaccordance with various aspects of the present disclosure;

FIG. 2 shows a diagram of aspects of discovery scan procedures for usein wireless communication, in accordance with various aspects of thepresent disclosure;

FIG. 3 shows a diagram of aspects of discovery scan procedures for usein wireless communication, in accordance with various aspects of thepresent disclosure;

FIG. 4 shows a diagram of aspects of discovery scan procedures for usein wireless communication, in accordance with various aspects of thepresent disclosure;

FIG. 5 shows a diagram of aspects of discovery scan procedures for usein wireless communication, in accordance with various aspects of thepresent disclosure;

FIG. 6 shows a block diagram of a device configured for use in wirelesscommunication, in accordance with various aspects of the presentdisclosure;

FIG. 7 shows a block diagram of a device configured for use in wirelesscommunication, in accordance with various aspects of the presentdisclosure;

FIG. 8 shows a block diagram of a user equipment for use in wirelesscommunications, in accordance with various aspects of the presentdisclosure;

FIG. 9 shows a block diagram of an apparatus for use in wirelesscommunication, in accordance with various aspects of the presentdisclosure;

FIG. 10 shows a block diagram of a base station (e.g., a base stationforming part or all of an eNB) for use in wireless communications, inaccordance with various aspects of the present disclosure;

FIG. 11 is a flow chart illustrating an example of a method for wirelesscommunication, in accordance with various aspects of the presentdisclosure;

FIG. 12 is a flow chart illustrating an example of a method for wirelesscommunication, in accordance with various aspects of the presentdisclosure;

FIG. 13 is a flow chart illustrating an example of a method for wirelesscommunication, in accordance with various aspects of the presentdisclosure; and

FIG. 14 is a flow chart illustrating an example of a method for wirelesscommunication, in accordance with various aspects of the presentdisclosure.

DETAILED DESCRIPTION

UEs in an active communication session (e.g., in a radio resourcecontrol (RRC) connected mode) may communicate with a serving basestation using one or more frequencies of a frequency band. A monitoringUE, attempting to receive a discovery signal from an announcing UEoperating on a different frequency (e.g., in a different frequency band)than the serving base station of the monitoring UE, may tune a receivechain away from the frequency of the serving base station and to thefrequency of the announcing UE. As a result, the monitoring UE may notbe able to receive certain downlink transmissions from the monitoringUE's serving base station while the monitoring UE scans for thediscovery signal from the announcing UE. Accordingly, it may bebeneficial for the monitoring UE to inform the serving base stationabout the monitoring UE's intention to perform the discovery scanprocedure, which may result in skipping the certain downlinktransmissions from the serving base station.

According to aspects of the present description, a monitoring UE mayinform a serving base station of the monitoring UE's intention toperform a discovery procedure in a different, target frequency (intra orinter public land mobile network (PLMN)) by informing the serving basestation about the target frequency, i.e., the frequency of theannouncing UE. In some examples, the monitoring UE may use theSLUEInfoMsg field to convey the information. In some examples, themonitoring UE may inform the serving base station whether the monitoringUE is capable of skipping downlink transmissions while in anRRC_CONNECTED/non-discontinuous reception (DRX) mode with the servingbase station. If the monitoring UE supports autonomously skippingcertain downlink transmissions, the monitoring UE may autonomously skipthe downlink transmissions during the discovery procedure. Additionallyor alternatively, the serving base station may respond to the monitoringUE and permit or deny the monitoring UE from participating in thediscovery procedure.

The following description provides examples, and is not limiting of thescope, applicability, or examples set forth in the claims. Changes maybe made in the function and arrangement of elements discussed withoutdeparting from the scope of the disclosure. Various examples may omit,substitute, or add various procedures or components as appropriate. Forinstance, the methods described may be performed in an order differentfrom that described, and various steps may be added, omitted, orcombined. Also, features described with respect to some examples may becombined in other examples.

FIG. 1 illustrates an example of a wireless communications system 100 inaccordance with various aspects of the disclosure. The wirelesscommunications system 100 includes base stations 105, UEs 115, and acore network 130. The core network 130 may provide user authentication,access authorization, tracking, Internet Protocol (IP) connectivity, andother access, routing, or mobility functions. The base stations 105interface with the core network 130 through backhaul links 132 (e.g.,S1, etc.) and may perform radio configuration and scheduling forcommunication with the UEs 115, or may operate under the control of abase station controller (not shown). In various examples, the basestations 105 may communicate, either directly or indirectly (e.g.,through core network 130), with each other over backhaul links 134(e.g., X1, etc.), which may be wired or wireless communication links.

The base stations 105 may wirelessly communicate with the UEs 115 viaone or more base station antennas. Each of the base station 105 sitesmay provide communication coverage for a respective geographic coveragearea 110. In some examples, base stations 105 may be referred to as abase transceiver station, a radio base station, an access point, a radiotransceiver, a NodeB, eNodeB (eNB), Home NodeB, a Home eNodeB, or someother suitable terminology. The geographic coverage area 110 for a basestation 105 may be divided into sectors making up only a portion of thecoverage area (not shown). The wireless communications system 100 mayinclude base stations 105 of different types (e.g., macro and/or smallcell base stations). There may be overlapping geographic coverage areas110 for different technologies.

In some examples, the wireless communications system 100 is an LTE/LTE-Anetwork. In LTE/LTE-A networks, the term evolved Node B (eNB) may begenerally used to describe the base stations 105, while the term UE maybe generally used to describe the UEs 115. The wireless communicationssystem 100 may be a Heterogeneous LTE/LTE-A network in which differenttypes of eNBs provide coverage for various geographical regions. Forexample, each eNB or base station 105 may provide communication coveragefor a macro cell, a small cell, and/or other types of cell. The term“cell” is a 3GPP term that can be used to describe a base station, acarrier or component carrier associated with a base station, or acoverage area (e.g., sector, etc.) of a carrier or base station,depending on context.

A macro cell generally covers a relatively large geographic area (e.g.,several kilometers in radius) and may allow unrestricted access by UEswith service subscriptions with the network provider. A small cell is alower-powered base station, as compared with a macro cell, that mayoperate in the same or different (e.g., licensed, unlicensed, etc.)frequency bands as macro cells. Small cells may include pico cells,femto cells, and micro cells according to various examples. A pico cellmay cover a relatively smaller geographic area and may allowunrestricted access by UEs with service subscriptions with the networkprovider. A femto cell also may cover a relatively small geographic area(e.g., a home) and may provide restricted access by UEs having anassociation with the femto cell (e.g., UEs in a closed subscriber group(CSG), UEs for users in the home, and the like). An eNB for a macro cellmay be referred to as a macro eNB. An eNB for a small cell may bereferred to as a small cell eNB, a pico eNB, a femto eNB or a home eNB.An eNB may support one or multiple (e.g., two, three, four, and thelike) cells (e.g., component carriers).

The wireless communications system 100 may support synchronous orasynchronous operation. For synchronous operation, the base stations mayhave similar frame timing, and transmissions from different basestations may be approximately aligned in time. For asynchronousoperation, the base stations may have different frame timing, andtransmissions from different base stations may not be aligned in time.The techniques described herein may be used for either synchronous orasynchronous operations.

The communication networks that may accommodate some of the variousdisclosed examples may be packet-based networks that operate accordingto a layered protocol stack. In the user plane, communications at thebearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based.A Radio Link Control (RLC) layer may perform packet segmentation andreassembly to communicate over logical channels. A Medium Access Control(MAC) layer may perform priority handling and multiplexing of logicalchannels into transport channels. The MAC layer may also use Hybrid ARQ(HARD) to provide retransmission at the MAC layer to improve linkefficiency. In the control plane, the Radio Resource Control (RRC)protocol layer may provide establishment, configuration, and maintenanceof an RRC connection between a UE 115 and the base stations 105 or corenetwork 130 supporting radio bearers for the user plane data. At thePhysical (PHY) layer, the transport channels may be mapped to Physicalchannels.

The UEs 115 are dispersed throughout the wireless communications system100, and each UE 115 may be stationary or mobile. A UE 115 may alsoinclude or be referred to by those skilled in the art as a mobilestation, a subscriber station, a mobile unit, a subscriber unit, awireless unit, a remote unit, a mobile device, a wireless device, awireless communications device, a remote device, a mobile subscriberstation, an access terminal, a mobile terminal, a wireless terminal, aremote terminal, a handset, a user agent, a mobile client, a client, orsome other suitable terminology. A UE 115 may be a cellular phone, apersonal digital assistant (PDA), a wireless modem, a wirelesscommunication device, a handheld device, a tablet computer, a laptopcomputer, a cordless phone, a wireless local loop (WLL) station, or thelike. A UE may be able to communicate with various types of basestations and network equipment including macro eNBs, small cell eNBs,relay base stations, and the like.

The communication links 125 shown in wireless communications system 100may include uplink (UL) transmissions from a UE 115 to a base station105, and/or downlink (DL) transmissions, from a base station 105 to a UE115. The downlink transmissions may also be called forward linktransmissions while the uplink transmissions may also be called reverselink transmissions. Each communication link 125 may include one or morecarriers, where each carrier may be a signal made up of multiplesub-carriers (e.g., waveform signals of different frequencies) modulatedaccording to the various radio technologies described above. Eachmodulated signal may be sent on a different sub-carrier and may carrycontrol information (e.g., reference signals, control channels, etc.),overhead information, user data, etc. The communication links 125 maytransmit bidirectional communications using FDD (e.g., using pairedspectrum resources) or TDD operation (e.g., using unpaired spectrumresources). Frame structures for FDD (e.g., frame structure type 1) andTDD (e.g., frame structure type 2) may be defined.

In some embodiments of the system 100, base stations 105 and/or UEs 115may include multiple antennas for employing antenna diversity schemes toimprove communication quality and reliability between base stations 105and UEs 115. Additionally or alternatively, base stations 105 and/or UEs115 may employ multiple-input, multiple-output (MIMO) techniques thatmay take advantage of multi-path environments to transmit multiplespatial layers carrying the same or different coded data.

Wireless communications system 100 may support operation on multiplecells or carriers, a feature which may be referred to as carrieraggregation (CA) or multi-carrier operation. A carrier may also bereferred to as a component carrier (CC), a layer, a channel, etc. Theterms “carrier,” “component carrier,” “cell,” and “channel” may be usedinterchangeably herein. A UE 115 may be configured with multipledownlink CCs and one or more uplink CCs for carrier aggregation. Carrieraggregation may be used with both FDD and TDD component carriers.

Wireless communications system 100 may support inter-frequency and, insome examples, inter-PLMN D2D discovery procedures. For example, amonitoring UE 115 may be communicating with a serving base station 105using a first frequency of a first frequency band. The monitoring UE 115may intend to establish a direct D2D communication link with aneighboring UE 115 that transmits D2D discovery signals on a secondfrequency of a second frequency band. The monitoring UE 115 may know, apriori, what frequencies the neighboring UE 115 transmits a discoverysignals on, e.g., the second frequency. The monitoring UE 115 may becommunicating with the serving base station 105 and know that tuning tothe second frequency may result in skipping one or more downlinktransmissions from the serving base station 105. Accordingly, themonitoring UE 115 may inform the serving base station 105 of anintention to monitor for the discovery signals on the second frequencyby sending information associated with performing the discovery scanprocedure on the second frequency during a discovery scan interval. Themonitoring UE 115 may determine a capability to skip a portions of thedownlink transmissions from the serving base station during thediscovery scan interval. In some examples, the monitoring UE 115 maysupport autonomously skipping the downlink transmissions during thediscovery scan interval and, therefore, sending the information to theserving base station 105 may not affect the serving base station 105with regard to performing the discovery scan procedure.

In some examples, the serving base station 105 may receive theinformation from the monitoring UE 115 and may send a response to themonitoring UE 115 indicating whether the monitoring UE 115 is allowed toskip some or all of the downlink transmissions during the discovery scaninterval. Accordingly, the serving base station 105 may control whetherthe monitoring UE 115 may perform the discovery scan procedure and skipthe downlink transmissions. In some examples, the serving base station105 may support partial downlink transmission skipping and may includein the response, for example, an indication of which downlinktransmissions can be skipped and which downlink transmissions cannot beskipped.

FIG. 2 is a diagram 200 illustrating aspects of D2D discovery signalingprocedures, in accordance with various aspects of the presentdisclosure. The diagram 200 may illustrate aspects of the wirelesscommunications system 100 of FIG. 1. The diagram 200 includes a UE 115-aand a base station 105-a. The UE 115-a may be an example of one or moreof the UEs 115 described above with respect to FIG. 1. The UE 115-a maybe a monitoring UE interested in performing a discovery scan procedurewith an announcing UE (not shown). The base station 105-a may be anexample of one or more of the base stations 105 described above withrespect to FIG. 1. The base station 105-a may be a serving base stationof the UE 115-a. Generally, the diagram 200 illustrates aspects ofimplementing D2D discovery procedure signaling protocols in wirelesscommunication systems. In some examples, a system device, such as one ofthe UEs 115 and/or base station 105, may execute one or more sets ofcodes to control the functional elements of the device to perform someor all of the functions described below.

At block 205, the UE 115-a may be communicating with base station 105-ausing a first frequency of a first frequency band. For example, the UE115-a may exchange various communications 210 with the base station105-a while in an active communication session (e.g., RRC_connectedmode). The active communication session may include the UE 115-a sendinguplink transmissions to the base stations 105-a and receiving downlinktransmissions from the base station 105-a. The downlink transmissionsmay include one or more resource elements (REs) of a resource block(RB), the RB being a slot within a subframe. In some examples, thedownlink transmissions may include REs spread across multiple slotsand/or multiple subframes. In some examples, a bitmap may representwhich REs are scheduled for downlink transmissions to the UE 115-a.

At block 215, the UE 115-a may transmit, to the base station 105-a,information associated with performing a scan procedure on a secondfrequency in a second frequency band during a discovery scan interval.The discovery scan information 220 may include information indicative ofthe second frequency. The second frequency may be different from thefirst frequency. Accordingly, the UE 115-a may retune at least onereceive chain away from the first frequency and to the second frequencyduring the discovery scan interval.

In some examples, the discovery scan information 220 may also includetiming information associated with the discovery scan interval. Forexample, the timing information may indicate during which subframes theUE 115-a may perform the discovery scan procedure, and by extensionwhich subframes of the downlink transmissions from the base station105-a that the UE 115-a may skip during the scan interval. In someexamples, the timing information may account for time associated withtuning the receive chain away from the first frequency to the secondfrequency and back to the first frequency, for timing differencesbetween the base station 105-a and the announcing UE broadcasting thediscovery signal, and the like.

At block 225, the UE 115-a may identify a capability to skip one or moredownlink transmissions from the base station 105-a during the scaninterval. As will be described in greater detail below, the ability ofthe UE 115-a to skip the one or more downlink transmissions may bedetermined autonomously by the UE 115-a, by the base station 105-a, orby coordination between the UE 115-a and the base station 105-a.

FIG. 3 is a diagram 300 illustrating aspects of D2D discovery signalingprocedures, in accordance with various aspects of the presentdisclosure. The diagram 300 may illustrate aspects of the wirelesscommunications system 100 of FIG. 1. The diagram 300 includes a UE 115-band a base station 105-b. The UE 115-b may be an example of one or moreof the UEs 115 described above with respect to FIG. 1. The UE 115-b maybe a monitoring UE interested in performing a discovery scan procedurewith an announcing UE (not shown). The base station 105-b may be anexample of one or more of the base stations 105 described above withrespect to FIG. 1. The base station 105-b may be a serving base stationof the UE 115-a. Generally, the diagram 300 illustrates aspects ofimplementing D2D discovery procedure signaling protocols in wirelesscommunication systems. In some examples, a system device, such as one ofthe UEs 115 and/or base station 105, may execute one or more sets ofcodes to control the functional elements of the device to perform someor all of the functions described below.

At block 305, the UE 115-b may be communicating with base station 105-busing a first frequency of a first frequency band. For example, the UE115-b may exchange various communications 310 with the base station105-b while in an active communication session (e.g., RRC_connectedmode). The active communication session may include the UE 115-b sendinguplink transmissions to the base stations 105-b and receiving downlinktransmissions from the base station 105-b. The downlink transmissionsmay include one or more REs of a RB within a subframe.

At block 315, the UE 115-b may transmit, to the base station 105-b,information associated with performing a scan procedure on a secondfrequency in a second frequency band during a discovery scan interval.The discovery scan information 320 may include information indicative ofthe second frequency. The second frequency may be different from thefirst frequency. Accordingly, the UE 115-b may need to retune at leastone receive chain away from the first frequency and to the secondfrequency during the discovery scan interval. In some examples, thediscovery scan information 320 may also include timing informationassociated with the discovery scan interval, e.g., timing informationthat accounts for receive chain tuning time, asynchronous timing betweenthe base station 105-b and the announcing UE broadcasting the discoverysignal, etc.

At block 325, the UE 115-b may identify a capability to skip one or moredownlink transmissions from the base station 105-a during the scaninterval. The UE 115-b may identify the skip capability autonomously,i.e., without receiving a response or information from the base station105-b. For example, the UE 115-b may be configured to support autonomousdownlink transmission skipping during the discovery scan interval. Insome examples, the discovery scan interval may be small with respect tothe active communications 310 (e.g., one (1) percent of the time ascompared to communications 310) and therefore the UE 115-b may beenabled to perform the discovery scan procedure and skip the downlinktransmissions. The UE 115-b may, as one non-limiting example, rely onhybrid automatic repeat-request (HARD) re-transmission procedures torecover any skipped downlink transmissions.

In another example, the discovery scan information 320 may provide anindication to the base station 105-b that the UE 115-b may beunavailable during the discovery scan interval. Accordingly, the basestation 105-b may reschedule a portion of the downlink transmissions topermit the UE 115-b to perform the discovery scan procedure and receivethe downlink transmissions before and/or afterwards.

At block 330, the UE 115-b may retune at least one receive chain awayfrom the first frequency and to the second frequency to perform thediscovery scan procedure. For example, the UE 115-b may retune one ormore receive chains to the second frequency to permit reception ofdiscovery signals broadcast from announcing UE(s). In some examples, theannouncing UE may be associated with a different carrier than the UE115-b, e.g., a different PLMN.

At block 335, the UE 115-b may perform the discovery scan procedure andmay skip the one or more downlink transmissions from the base station105-b during the discovery scan procedure. For example, the receivechain(s) tuned to the second frequency may prohibit reception ofdownlink transmissions from the base station 105-b on the firstfrequency.

FIG. 4 is a diagram 400 illustrating aspects of D2D discovery signalingprocedures, in accordance with various aspects of the presentdisclosure. The diagram 400 may illustrate aspects of the wirelesscommunications system 100 of FIG. 1. The diagram 400 includes a UE 115-cand a base station 105-c. The UE 115-c may be an example of one or moreof the UEs 115 described above with respect to FIG. 1. The UE 115-c maybe a monitoring UE interested in performing a discovery scan procedurewith an announcing UE (not shown). The base station 105-c may be anexample of one or more of the base stations 105 described above withrespect to FIG. 1. The base station 105-c may be a serving base stationof the UE 115-c. Generally, the diagram 400 illustrates aspects ofimplementing D2D discovery procedure signaling protocols in wirelesscommunication systems. In some examples, a system device, such as one ofthe UEs 115 and/or base stations 105, may execute one or more sets ofcodes to control the functional elements of the device to perform someor all of the functions described below.

At block 405, the UE 115-c may be communicating with base station 105-cusing a first frequency of a first frequency band. For example, the UE115-c may exchange various communications 410 with the base station105-c while in an active communication session (e.g., RRC_connectedmode). The active communication session may include the UE 115-c sendinguplink transmissions to the base stations 105-c and receiving downlinktransmissions from the base station 105-c.

At block 415, the UE 115-c may transmit, to the base station 105-c,information associated with performing a scan procedure on a secondfrequency in a second frequency band during a discovery scan interval.The discovery scan information 420 may include information indicative ofthe second frequency. The second frequency may be different from thefirst frequency. Accordingly, the UE 115-c may need to retune at leastone receive chain away from the first frequency and to the secondfrequency during the discovery scan interval. In some examples, thediscovery scan information 420 may also include timing informationassociated with the discovery scan interval.

At block 425, the base station 105-c may identify a capability for theUE 115-c to skip one or more downlink transmissions from the basestation 105-c during the scan interval. For example, the base station105-c may determine which, if any, of the downlink transmissions the UE115-c can skip during the discovery scan interval. In some examples, thebase station 105-c may identify downlink transmissions that can beskipped or cannot be skipped based on a type of the downlinktransmission, a priority level associated with the downlinktransmissions, and the like.

At block 430, the base station 105-c may send a response 435 to the UE115-c to convey information indicative of the capability of the UE 115-cto skip the one or more downlink transmissions. The response mayauthorize the UE 115-c to skip certain downlink transmissions during thediscovery scan interval and/or may prohibit the UE 115-c to skip certaindownlink transmissions during the discovery scan interval.

If authorized, at block 440 the UE 115-c may retune at least one receivechain away from the first frequency and to the second frequency toperform the discovery scan procedure. For example, the UE 115-c mayretune one or more receive chains to the second frequency to permitreception of discovery signals broadcast from announcing UE(s). In someexamples, the announcing UE may be associated with a different carrierthan the UE 115-c, e.g., a different PLMN.

If authorized, at block 445, the UE 115-c may perform the discovery scanprocedure and skip the one or more downlink transmissions from the basestation 105-c during the discovery scan procedure. For example, thereceive chain(s) tuned to the second frequency may prohibit reception ofdownlink transmissions from the base station 105-c on the firstfrequency.

FIG. 5 is a diagram 500 illustrating aspects of D2D discovery signalingprocedures, in accordance with various aspects of the presentdisclosure. The diagram 500 may illustrate aspects of the wirelesscommunications system 100 of FIG. 1. The diagram 500 includes a UE 115-dand a base station 105-d. The UE 115-d may be an example of one or moreof the UEs 115 described above with respect to FIG. 1. The UE 115-d maybe a monitoring UE interested in performing a discovery scan procedurewith an announcing UE (not shown). The base station 105-d may be anexample of one or more of the base stations 105 described above withrespect to FIG. 1. The base station 105-d may be a serving base stationof the UE 115-d. Generally, the diagram 500 illustrates aspects ofimplementing D2D discovery procedure signaling protocols in wirelesscommunication systems. In some examples, a system device, such as one ofthe UEs 115 and/or base stations 105, may execute one or more sets ofcodes to control the functional elements of the device to perform someor all of the functions described below.

At block 505, the UE 115-d may be communicating with base station 105-dusing a first frequency of a first frequency band. For example, the UE115-d may exchange various communications 410 with the base station105-d while in an active communication session (e.g., RRC_connectedmode). The active communication session may include the UE 115-d sendinguplink transmissions to the base stations 105-d and receiving downlinktransmissions from the base station 105-d.

At block 515, the UE 115-d may transmit, to the base station 105-d,information associated with performing a scan procedure on a secondfrequency in a second frequency band during a discovery scan interval.The discovery scan information 520 may include information indicative ofthe second frequency. The second frequency may be different from thefirst frequency. Accordingly, the UE 115-d may need to retune at leastone receive chain away from the first frequency and to the secondfrequency during the discovery scan interval. In some examples, thediscovery scan information 520 may also include timing informationassociated with the discovery scan interval.

At block 525, the base station 105-d may identify a capability for theUE 115-d to skip one or more downlink transmissions from the basestation 105-d during the scan interval. In the example diagram 500, thebase station 105-d may authorize the UE 115-d to skip at least a portionof the downlink transmissions occurring during the discovery scaninterval.

At block 530, the base station 105-d may determine which of the downlinktransmissions the UE 115-d can skip during the discovery scan interval.In some examples, the base station 105-d may identify downlinktransmissions that can be skipped or cannot be skipped based on a typeof the downlink transmission, a priority level associated with thedownlink transmissions, and the like.

At block 535, the base station 105-d may send a response 540 to the UE115-d to convey information indicative of the capability of the UE 115-dto skip the one or more downlink transmissions. The response mayauthorize the UE 115-d to skip certain downlink transmissions during thediscovery scan interval and/or may prohibit the UE 115-d from skippingcertain downlink transmissions during the discovery scan interval. Inone example, the response 540 may include a bitmap that corresponds tothe skippable downlink transmissions and the non-skippable downlinktransmissions. The bitmap may correspond to REs of subframes associatedwith the downlink transmissions.

At block 545 the UE 115-d may retune at least one receive chain awayfrom the first frequency and to the second frequency to perform thediscovery scan procedure. For example, the UE 115-d may retune one ormore receive chains to the second frequency to permit reception ofdiscovery signals broadcast from announcing UE(s). In one example, theUE 115-d may retune one receive chain to the second frequency but keep asecond receive chain tuned to the first frequency to receive thenon-skippable downlink transmissions during the discovery scan interval.

At block 550, the UE 115-d may perform the discovery scan procedure andskip the skippable downlink transmissions and receive the non-skippabledownlink transmissions from the base station 105-d during the discoveryscan procedure. For example, at least one receive chain may be tuned tothe second frequency and at least one receive chain may be tuned to thefirst frequency during the discovery scan interval.

FIG. 6 shows a block diagram 600 of a device 605 for use in wirelesscommunication, in accordance with various aspects of the presentdisclosure. The device 605 may be an example of one or more aspects of aUE 115 described with reference to FIGS. 1-5. The device 605 may includea receiver 610, a UE discovery manager 615, and/or a transmitter 620.The device 605 may also be or include a processor (not shown). Each ofthese modules may be in communication with each other.

The components of the device 605 may, individually or collectively, beimplemented using one or more application-specific integrated circuits(ASICs) adapted to perform some or all of the applicable functions inhardware. Alternatively, the functions may be performed by one or moreother processing units (or cores), on one or more integrated circuits.In other examples, other types of integrated circuits may be used (e.g.,Structured/Platform ASICs, Field Programmable Gate Arrays (FPGAs), andother Semi-Custom ICs), which may be programmed in any manner known inthe art. The functions of each module may also be implemented, in wholeor in part, with instructions embodied in a memory, formatted to beexecuted by one or more general or application-specific processors.

The receiver 610 may receive information such as packets, user data,and/or control information associated with various information channels(e.g., control channels, data channels, etc.). The receiver 610 may beconfigured to receive various signals associated with D2D discovery andassociated signaling protocols. Information may be passed on to the UEdiscovery manager 615, and to other components of the device 605.

The UE discovery manager 615 may monitor, control, or otherwise manageone or more aspects of a D2D discovery operations for the device 605.For example, the UE discovery manager 615 may, alone or in cooperationwith other components of the device 605, manage aspects of communicatingwith a serving base station using a first frequency in a first frequencyband. The communications with the serving base station may occur duringan active communication session between the device 605 and the servingbase station. The UE discovery manager 615 may transmit, to the servingbase station, information associated with performing a discovery scanprocedure on a second frequency in a second frequency band during adiscovery scan interval. The first frequency may be different from thesecond frequency. In some examples, the discovery scan procedure may bean inter-PLMN procedure where the announcing UE is associated with adifferent carrier or service provider than the serving base station. TheUE discovery manager 615 may identify a capability to skip one or moredownlink transmissions from the serving base station during thediscovery scan interval. For example, the device 605 and/or the servingbase station may determine which, if any, of the downlink transmissionsthe device 605 can skip during the discovery scan interval.

The transmitter 620 may transmit the one or more signals received fromother components of the device 605. The transmitter 620 may transmitvarious signals associated with D2D discovery and associated signalingprotocols. In some examples, the transmitter 620 may be collocated withthe receiver 610 in a transceiver module.

FIG. 7 shows a block diagram 700 of a device 605-a for use in wirelesscommunication, in accordance with various examples. The device 605-a maybe an example of one or more aspects of a UE 115 described withreference to FIGS. 1-5. The device 605-a may also be an example of adevice 605 described with reference to FIG. 6. The device 605-a mayinclude a receiver 610-a, a UE discovery manager 615-a, and/or atransmitter 620-a, which may be examples of the corresponding modules ofdevice 605. The device 605-a may also include a processor (not shown).Each of these components may be in communication with each other. The UEdiscovery manager 615-a may include a skip capability manager 705, adiscovery scan manager 710, and/or a downlink resource skip manager 715.The receiver 610-a and the transmitter 620-a may perform the functionsof the receiver 610 and the transmitter 620 of FIG. 6, respectively.

The skip capability manager 705 may monitor, control, or otherwisemanage one or more aspects of identifying a skip capability for thedevice 605-a. For example, the device 605-a may be communicating with aserving base station using a first frequency in a first frequency bandand the skip capability manager 705 may transmit, to the serving basestation, information associated with a discovery scan procedure on asecond frequency in a second frequency band during a discovery scaninterval. The first frequency may be different from the second frequencyand, in some examples, the serving base station may be associated with afirst network and the discovery scan procedure may be associated with asecond network, the first network being different from the secondnetwork (e.g., inter-PLMN discovery procedure). The discovery scanprocedure may be a D2D discovery procedure.

In some aspects, the skip capability manager 705 may independentlydetermine whether the device 605-a can skip the one or more downlinktransmissions during the discovery scan interval. In other aspects, theskip capability manager 705 may receive a response from the serving basestation providing an indication of whether the device 605-a can skip theone or more downlink transmission during the discovery scan interval.

In some aspects, the information transmitted to the serving base stationassociated with performing the discovery scan procedure may include thesecond frequency. Thus, the device 605-a sending the second frequencymay provide an indication to the serving base station that the device605-a intends or desires to skip the one or more downlink transmissionsduring the discovery scan interval.

In some aspects, the information transmitted to the serving base stationassociated with performing the discovery scan procedure may includetiming information associated with the discovery scan interval. Thetiming information may include information indicative of the one or moresubframes where the device 605-a may skip the one or more downlinktransmission from the serving base station. For example, the timinginformation may indicate which subframes the discovery scan intervalencompasses. In some examples, the timing information may be based ontiming differences between the serving base station and the announcingUE. For example, the skip capability manager 705 may select thesubframes of the discovery scan interval based on the timing difference(e.g., to account for partially overlapping subframes) between theserving base station and the device transmitting the discovery signalassociated with the discovery scan procedure.

In some aspects, the timing information may account for tuning time ofthe device 605-a. For example, the skip capability manager 705 maydetermine a timing parameter associated with tuning to and tuning awayfrom the second frequency and select the subframes to account for thisparameter. Thus, the discovery scan interval may include, in someexamples, one or more subframes based on the time to tune to the secondfrequency, the time to perform the discovery scan procedure, and thetime to tune away from the second frequency, accounting for any timingdifferences between the serving base station and the announcing UE.

The discovery scan manager 710 may monitor, control, or otherwise manageone or more aspects of discovery scan operations for the device 605-a.For example, the discovery scan manager 710 may tune to the secondfrequency. As discussed, the device 605-a may determine that the device605-a can skip the downlink transmissions during the discovery scaninterval without receiving a response from the base station.Accordingly, the discovery scan manager 710 may tune to the secondfrequency during (or immediately prior to considering frame timing ofthe announcing UE) the discovery scan interval.

In another example, the serving base station may send a response to thedevice 605-a indicating whether the device 605-a is allowed to skip theone or more downlink transmissions during the discovery scan interval.In some examples, the response may include an indication that the devicemay skip only a portion of the downlink transmissions. The response may,for example, include a bitmap associated with which downlinktransmissions can be skipped and which downlink transmissions cannot beskipped. Accordingly, the discovery scan manager 710 may tune to thesecond frequency during the discovery scan interval when permitted bythe serving base station and during the skippable portions of thedownlink transmissions.

The downlink resource skip manager 715 may monitor, control, orotherwise manage one or more aspects of skipping downlink transmissionsfor the device 605-a. For example, the downlink resource skip manager715 may manage aspects of skipping one or more downlink transmissionsduring a discovery scan interval. As discussed, the device 605-a mayautonomously identify a skip capability and the downlink resource skipmanager 715 may skip the downlink transmissions during the discoveryscan interval. In other examples, the downlink resource skip manager 715may skip all or some of the downlink transmissions during the scaninterval when permitted and as instructed by the serving base stations.For example, the response from the serving base station may permitskipping a first portion of the one or more downlink transmissionsduring the discovery scan interval and receiving a second portion of theone or more downlink transmissions during the discovery scan interval.The response may include a bitmap associated with which portions of thedownlink transmission can be skipped and which portions cannot beskipped, i.e., are to be received. The downlink resource skip manager715 may manage skipping the permitted portions of the downlinktransmissions.

FIG. 8 illustrates a block diagram of portions of a system 800 includinga user equipment 115-e for use in wireless communication, in accordancewith various aspects of the present disclosure. In some examples, the UE115-e may be an example of the UEs 115 (e.g., a monitoring UE) describedwith respect to FIGS. 1-5, and/or devices 605 of FIGS. 6 and 7. UE 115-emay include a UE discovery manager 615-b which may be an example of andperform the functions of the UE discovery manager 615 described withrespect to FIGS. 6 and 7. UE 115-e may include components forbi-directional voice and data communications including components fortransmitting communications and components for receiving communications.For example, UE 115-e may communicate bi-directionally with basestations and/or other UEs.

UE 115-e may include a processor 805, and memory 815 (e.g., includingsoftware (SW)) 820, a transceiver 835, and one or more antenna(s) 840,each of which may communicate, directly or indirectly, with one another(e.g., via buses 845). The transceiver 835 may communicatebi-directionally, via the antenna(s) 840 or wired or wireless links,with one or more networks, as described above. For example, thetransceiver 835 may communicate bi-directionally with a base station oranother UE. The transceiver 835 may include a modem to modulate thepackets and provide the modulated packets to the antenna(s) 840 fortransmission, and to demodulate packets received from the antenna(s)840. While UE 115-e may include a single antenna 840, UE 115-e may alsohave multiple antennas 840 capable of concurrently transmitting orreceiving multiple wireless transmissions.

The memory 815 may include random access memory (RAM) and read onlymemory (ROM). The memory 815 may store computer-readable,computer-executable software/firmware code 820 including instructionsthat, when executed, cause the processor 805 to perform variousfunctions described herein (e.g., signaling protocols for D2D discoveryprocedures, etc.). Alternatively, the software/firmware code 820 may notbe directly executable by the processor 805 but cause a computer (e.g.,when compiled and executed) to perform functions described herein. Theprocessor 805 may include an intelligent hardware device, (e.g., acentral processing unit (CPU), a microcontroller, an ASIC, etc.).

The UE discovery manager 615-b may be configured to perform and/orcontrol some or all of the features and/or functions described withreference to FIGS. 1-7 related to signaling protocols for D2D discoveryoperations for the UE 115-e. In some examples, the UE discovery manager615-b may communicate with a serving base station using a firstfrequency in a first frequency band, transmit to the serving basestation information associated with performing a discovery scanprocedure on a second frequency in a second frequency band during adiscovery scan interval (the first frequency being different from thesecond frequency), and identify a capability to skip one or moredownlink transmissions from the serving base station during thediscovery scan interval. The UE discovery manager 615-b, or portionsthereof, may include a processor, and/or some or all of the functions ofthe UE discovery manager 615-b may be performed by the processor 805and/or in connection with the processor 805. In some examples, the UEdiscovery manager 615-b may be an example of the UE discovery manager615 described with reference to FIGS. 6, and/or 7. For example, the UEdiscovery manager 615-b may include a skip capability manager 705-a, adiscovery scan manager 710-a, and/or a downlink resource skip manager715-a, which may be examples of and perform the functions of the skipcapability manager 705, the discovery scan manager 710, and/or thedownlink resource skip manager 715, respectively, described withreference to FIG. 7.

FIG. 9 shows a block diagram 900 of an apparatus 905 for use in wirelesscommunication, in accordance with various aspects of the presentdisclosure. In some examples, the apparatus 905 may be an example ofaspects of one or more of the base stations 105 described with referenceto FIGS. 1-5. The apparatus 905 may be a serving base station for amonitoring UE 115. In some examples, the apparatus 905 may be part orinclude an LTE/LTE-A eNB and/or an LTE/LTE-A base station. The apparatus905 may also be a processor. The apparatus 905 may include a receiver910, a base station discovery manager 915, and/or a transmitter 920.Each of these modules may be in communication with each other.

The components of the apparatus 905 may, individually or collectively,be implemented using one or more ASICs adapted to perform some or all ofthe applicable functions in hardware. Alternatively, the functions maybe performed by one or more other processing units (or cores), on one ormore integrated circuits. In other examples, other types of integratedcircuits may be used (e.g., Structured/Platform ASICs, FPGAs, and otherSemi-Custom ICs), which may be programmed in any manner known in theart. The functions of each component may also be implemented, in wholeor in part, with instructions embodied in a memory, formatted to beexecuted by one or more general or application-specific processors.

In some examples, the receiver 910 may include at least one radiofrequency (RF) receiver, such as an RF receiver operable to receivevarious signaling protocols associated with D2D discovery operations.The receiver 910 may be used to receive various types of data and/orcontrol signals (i.e., transmissions) over one or more communicationlinks of a wireless communication system, such as one or morecommunication links of the wireless communications system 100 describedwith reference to FIG. 1.

In some examples, the transmitter 920 may include at least one RFtransmitter, such as at least one RF transmitter operable to transmitvarious signaling protocols associated with D2D discovery procedures.The transmitter 90 may be used to transmit various types of data and/orcontrol signals (i.e., transmissions) over one or more communicationlinks of a wireless communication system, such as one or morecommunication links of the wireless communications system 100 describedwith reference to FIG. 1.

The base station discovery manager 915 may monitor, control, orotherwise manage one or more aspects of signaling protocols for D2Ddiscovery operations for the apparatus 905. For example, the basestation discovery manager 915 may manage aspects of communicating with aUE using a first frequency in a first frequency band. The base stationdiscovery manager 915 may manage aspects of receiving, from the UE,information associated with the UE performing a discovery scan procedureon a second frequency in a second frequency band during a discovery scaninterval, the second frequency being different from the first frequency.The base station discovery manager 915 may manage aspects of sending aresponse to the UE indicating whether the UE is allowed to skip one ormore downlink transmissions during the discovery scan interval. Forexample, the base station discovery manager 915 may determine whetherthe UE can skip the one or more downlink transmissions during thediscovery scan procedure.

In some aspects, the base station discovery manager 915 may manageaspects of receiving a capability message from the UE indicating the UEis capable of skipping the one or more downlink transmissions during thediscovery scan interval. The capability message may indicate whether theUE can support skipping the downlink transmissions.

In some aspects, the base station discovery manager 915 may manageaspects of the response identifying a first portion of the one or moredownlink transmissions the UE is allowed to skip during the discoveryscan interval and/or identifying a second portion of the one or moredownlink transmissions the UE is not allowed to skip during thediscovery scan interval. In one example, the response may include abitmap (e.g., 1's and 0's) indicating which downlink transmissions canbe skipped and which downlink transmissions cannot be skipped during thediscovery scan interval.

In some aspects, the base station discovery manager 915 may manageaspects of receiving timing information associated with the discoveryscan interval from the UE. The timing information may includeinformation identifying which subframe(s) are associated with thediscovery scan interval, e.g., which subframes the UE may perform thediscovery scan procedure.

FIG. 10 shows a block diagram 1000 of a base station 105-e (e.g., a basestation forming part or all of an eNB) for use in wirelesscommunication, in accordance with various aspects of the presentdisclosure. In some examples, the base station 105-e may be an exampleof aspects of one or more of the base stations 105 described withreference to FIGS. 1-5, and/or aspects of one or more of the apparatuses905 when configured as a base station, as described with reference toFIG. 9. The base station 105-e may be configured to implement orfacilitate at least some of the base station and/or apparatus featuresand functions described with reference to FIGS. 1-9.

The base station 105-e may include a base station processor 1010, a basestation memory 1020, at least one base station transceiver (representedby base station transceiver 1050), at least one base station antenna(represented by base station antenna(s) 1055), and/or a base stationdiscovery manager 915-a. The base station 105-e may also include one ormore of a base station communications manager 1030 and/or a networkcommunications manager 1040. Each of these modules may be incommunication with each other, directly or indirectly, over one or morebuses 1035.

The base station memory 1020 may include random access memory (RAM)and/or read-only memory (ROM). The base station memory 1020 may storecomputer-readable, computer-executable software/firmware code 1025containing instructions that are configured to, when executed, cause thebase station processor 1010 to perform various functions describedherein related to wireless communication (e.g., to perform signalingprotocols for D2D discovery operations in a wireless communicationsystem, etc.). Alternatively, the computer-readable, computer-executablesoftware/firmware code 1025 may not be directly executable by the basestation processor 1010 but be configured to cause the base station 105-e(e.g., when compiled and executed) to perform various of the functionsdescribed herein.

The base station processor 1010 may include an intelligent hardwaredevice, e.g., a central processing unit (CPU), a microcontroller, anASIC, etc. The base station processor 1010 may process informationreceived through the base station transceiver 1050, the base stationcommunications manager 1030, and/or the network communications manager1040. The base station processor 1010 may also process information to besent to the base station transceiver 1050 for transmission through theantenna(s) 1055, to the base station communications manager 1030, fortransmission to one or more other base stations 105-f and 105-g, and/orto the network communications manager 1040 for transmission to a corenetwork 1045, which may be an example of one or more aspects of the corenetwork 130 described with reference to FIG. 1. The base stationprocessor 1010 may handle, alone or in connection with the base stationdiscovery manager 915-a, various aspects of signaling protocolsassociated with D2D discovery operations for the base station 105-e.

The base station transceiver 1050 may include a modem configured tomodulate packets and provide the modulated packets to the base stationantenna(s) 1055 for transmission, and to demodulate packets receivedfrom the base station antenna(s) 1055. The base station transceiver 1050may, in some examples, be implemented as one or more base stationtransmitter modules and one or more separate base station receivermodules. The base station transceiver 1050 may support communications ina first radio frequency spectrum band and/or a second radio frequencyspectrum band. The base station transceiver 1050 may be configured tocommunicate bi-directionally, via the antenna(s) 1055, with one or moreUEs or devices, such as one or more of the UEs 115 described withreference to FIG. 1. The base station 105-e may, for example, includemultiple base station antennas 1055 (e.g., an antenna array). The basestation 105-e may communicate with the core network 1045 through thenetwork communications manager 1040. The base station 105-e may alsocommunicate with other base stations, such as the base stations 105-fand 105-g, using the base station communications manager 1030.

The base station discovery manager 915-a may be configured to performand/or control some or all of the features and/or functions describedwith reference to FIGS. 1-9 related to signaling protocols associatedwith D2D discovery operations for the base station 105-e. In someexamples, the base station discovery manager 915-a may manage aspects ofcommunicating with a UE using a first frequency in a first frequencyband. The base station discovery manager 915-a may manage aspects ofreceiving, from the UE, information associated with the UE performing adiscovery scan procedure on a second frequency in a second frequencyband during a discovery scan interval, the second frequency beingdifferent from the first frequency. The base station discovery manager915-a may manage aspects of sending a response to the UE indicatingwhether the UE is allowed to skip one or more downlink transmissionsduring the discovery scan interval. The base station discovery manager915-a, or portions thereof, may include a processor, and/or some or allof the functions of the base station discovery manager 915-a may beperformed by the base station processor 1010 and/or in connection withthe base station processor 1010. In some examples, the base stationdiscovery manager 915-a may be an example of the base station discoverymanager 915 described with reference to FIG. 9.

FIG. 11 shows a flowchart illustrating a method 1100 for wirelesscommunications, in accordance with various aspects of the presentdisclosure. The operations of method 1100 may be implemented by a UE 115or its components, and/or by a device 605 as described with reference toFIGS. 1-8. For example, the operations of method 1100 may be performedby the UE discovery manager 615 as described with reference to FIGS.6-8. In some examples, a UE 115 may execute a set of codes to controlthe functional elements of the UE 115 to perform the functions describedbelow. Additionally or alternatively, the UE 115 may perform aspects thefunctions described below using special-purpose hardware. Forconvenience, the functions of the method 1100 will be described withreference to a UE, such as a monitoring UE 115.

At block 1105, the method 1100 may include the UE communicating with aserving base station using a first frequency in a first frequency range.The UE may be communicating with the serving base station during anactive communication session where the UE is in an RRC_connected mode.The communication session may be associated with the UE receiving one ormore downlink transmissions from the serving base station.

At block 1110, the method 1100 may include the UE transmitting, to theserving base station, information associated with performing a discoveryscan procedure on a second frequency in a second frequency band during adiscovery scan interval. The second frequency may be different from thefirst frequency. The information transmitted may include an indicationof the second frequency. In some examples, the discovery scan proceduremay be an inter-PLMN D2D discovery scan procedure where the serving basestation and the announcing UE broadcasting the discovery signal areassociated with different carriers or network providers.

At block 1115, the method 1100 may include the UE identifying acapability to skip one or more downlink transmission from the servingbase station during the discovery scan interval. The UE may identify theskip capability autonomously and/or based on communications with theserving base station.

The operation(s) at blocks 1105, 1110, and/or 1115 may be performedusing the UE discovery manager 615 described with reference to FIGS.6-8.

Thus, the method 1100 may provide for wireless communication. It shouldbe noted that the method 1100 is just one implementation and that theoperations of the method 1100 may be rearranged or otherwise modifiedsuch that other implementations are possible.

FIG. 12 shows a flowchart illustrating a method 1200 for wirelesscommunications, in accordance with various aspects of the presentdisclosure. The operations of method 1200 may be implemented by a UE 115or its components, and/or by a device 605 as described with reference toFIGS. 1-8. For example, the operations of method 1200 may be performedby the UE discovery manager 615 as described with reference to FIGS.6-8. In some examples, a UE 115 may execute a set of codes to controlthe functional elements of the UE 115 to perform the functions describedbelow. Additionally or alternatively, the UE 115 may perform aspects thefunctions described below using special-purpose hardware. Forconvenience, the functions of the method 1200 will be described withreference to a UE, such as a monitoring UE 115.

At block 1205, the method 1200 may include the UE communicating with aserving base station using a first frequency in a first frequency range.The UE may be communicating with the serving base station during anactive communication session where the UE is in an RRC_connected mode.The communication session may be associated with the UE receiving one ormore downlink transmissions from the serving base station.

At block 1210, the method 1200 may include the UE transmitting, to theserving base station, information associated with performing a discoveryscan procedure on a second frequency in a second frequency band during adiscovery scan interval. The second frequency may be different from thefirst frequency. The information transmitted may include an indicationof the second frequency. In some examples, the discovery scan proceduremay be an inter-PLMN D2D discovery scan procedure where the serving basestation and the announcing UE broadcasting the discovery signal areassociated with different carriers or network providers.

At block 1215, the method 1200 may include the UE identifying acapability to skip one or more downlink transmission from the servingbase station during the discovery scan interval. The UE may identify theskip capability autonomously and at block 1220, tune to the secondfrequency during the discovery scan interval. That is, the UE maysupport skipping the one or more downlink transmissions during thediscovery scan interval without input from the serving base station. TheUE may tune a receive chain to the second frequency.

At block 1225, the method 1200 may include the UE skipping the one ormore transmissions from the serving base station during the discoveryscan interval. Tuning the receive chain to the second frequency mayresult in the UE skipping the one or more downlink transmissions fromthe serving base station.

The operation(s) at blocks 1205, 1210, 1215, 1220, and/or 1225 may beperformed using the UE discovery manager 615 described with reference toFIGS. 6-8.

Thus, the method 1200 may provide for wireless communication. It shouldbe noted that the method 1200 is just one implementation and that theoperations of the method 1200 may be rearranged or otherwise modifiedsuch that other implementations are possible.

FIG. 13 shows a flowchart illustrating a method 1300 for wirelesscommunications, in accordance with various aspects of the presentdisclosure. The operations of method 1300 may be implemented by a UE 115or its components, and/or by a device 605 as described with reference toFIGS. 1-8. For example, the operations of method 1300 may be performedby the UE discovery manager 615 as described with reference to FIGS.6-8. In some examples, a UE 115 may execute a set of codes to controlthe functional elements of the UE 115 to perform the functions describedbelow. Additionally or alternatively, the UE 115 may perform aspects thefunctions described below using special-purpose hardware. Forconvenience, the functions of the method 1300 will be described withreference to a UE, such as a monitoring UE 115.

At block 1305, the method 1300 may include the UE communicating with aserving base station using a first frequency in a first frequency range.The UE may be communicating with the serving base station during anactive communication session where the UE is in an RRC_connected mode.The communication session may be associated with the UE receiving one ormore downlink transmissions from the serving base station.

At block 1310, the method 1300 may include the UE transmitting, to theserving base station, information associated with performing a discoveryscan procedure on a second frequency in a second frequency band during adiscovery scan interval. The second frequency may be different from thefirst frequency. The information transmitted may include an indicationof the second frequency. In some examples, the discovery scan proceduremay be an inter-PLMN D2D discovery scan procedure where the serving basestation and the announcing UE broadcasting the discovery signal areassociated with different carriers or network providers.

At block 1315, the method 1300 may include the UE identifying acapability to skip one or more downlink transmission from the servingbase station during the discovery scan interval. For example, at block1320 the UE may receive a response from the serving base station andidentify the skip capability based on the response received from theserving base station. The response may provide an indication that the UEis allowed to skip all, allowed to skip a portion of, and/or allowed toskip none of the downlink transmissions from the serving base stationduring the discovery scan interval. That is, the UE may support skippingthe one or more downlink transmissions during the discovery scaninterval based, at least in part, on input received from the servingbase station.

At block 1325, the method 1300 may include the UE skipping the one ormore transmissions from the serving base station during the discoveryscan interval based at least in part on the received response. Theresponse may include information indicative of which portions of thedownlink transmissions can be skipped and which portions of the downlinktransmissions cannot be skipped during the discovery scan interval.

The operation(s) at blocks 1305, 1310, 1315, 1320, and/or 1325 may beperformed using the UE discovery manager 615 described with reference toFIGS. 6-8.

Thus, the method 1300 may provide for wireless communication. It shouldbe noted that the method 1300 is just one implementation and that theoperations of the method 1300 may be rearranged or otherwise modifiedsuch that other implementations are possible.

FIG. 14 shows a flowchart illustrating a method 1400 for wirelesscommunications, in accordance with various aspects of the presentdisclosure. The operations of method 1400 may be implemented by a basestation 105 or its components, and/or by an apparatus 905 as describedwith reference to FIGS. 1-5 and 9-10, respectively. For example, theoperations of method 1400 may be performed by the base station discoverymanager 915 as described with reference to FIGS. 9-10. In some examples,a base station 105 may execute a set of codes to control the functionalelements of the base station 105 to perform the functions describedbelow. Additionally or alternatively, the base station 105 may performaspects the functions described below using special-purpose hardware.For convenience, the functions of the method 1400 will be described withreference to a base station, such as a serving base station of amonitoring UE.

At block 1405, the method 1400 may include the base stationcommunicating with a UE using a first frequency in a first frequencyrange. The base station may be communicating with the UE during anactive communication session where the UE is in an RRC_connected mode.The communication session may be associated with the UE receiving one ormore downlink transmissions from the base station.

At block 1410, the method 1400 may include the base station receiving,from the UE, information associated with the UE performing a discoveryscan procedure on a second frequency in a second frequency band during adiscovery scan interval. The second frequency may be different from thefirst frequency. The information received may include an indication ofthe second frequency. In some examples, the discovery scan procedure maybe an inter-PLMN D2D discovery scan procedure where the base station andthe announcing UE broadcasting the discovery signal are associated withdifferent carriers or network providers.

At block 1415, the method 1400 may include the base station sending aresponse to the UE indicating whether the UE is allowed to skip one ormore downlink transmissions during the discovery scan interval. Forexample, the base station may identify a capability of the UE to skipthe one or more downlink transmission from the base station during thediscovery scan interval. In a partial-skip scenario, the response mayprovide an indication of a first portion of downlink transmissions thatcan be skipped and a second portion of downlink transmissions thatcannot be skipped during the discovery scan interval.

The operation(s) at blocks 1405, 1410, and/or 1415 may be performedusing the base station discovery manager 915 described with reference toFIGS. 9-10.

Thus, the method 1400 may provide for wireless communication. It shouldbe noted that the method 1400 is just one implementation and that theoperations of the method 1400 may be rearranged or otherwise modifiedsuch that other implementations are possible.

In some examples, aspects from two or more of the methods 1100-1400 maybe combined. It should be noted that the methods 1100, 1200, etc. arejust example implementations, and that the operations of the methods1100-1400 may be rearranged or otherwise modified such that otherimplementations are possible.

Techniques described herein may be used for various wirelesscommunications systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, andother systems. The terms “system” and “network” are often usedinterchangeably. A CDMA system may implement a radio technology such asCDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases 0 and Aare commonly referred to as CDMA2000 1×, 1×, etc. IS-856 (TIA-856) iscommonly referred to as CDMA2000 1×EV-DO, High Rate Packet Data (HRPD),etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. ATDMA system may implement a radio technology such as Global System forMobile Communications (GSM). An OFDMA system may implement a radiotechnology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA),IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM™, etc.UTRA and E-UTRA are part of Universal Mobile Telecommunication System(UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are newreleases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, andGSM are described in documents from an organization named “3rdGeneration Partnership Project” (3GPP). CDMA2000 and UMB are describedin documents from an organization named “3rd Generation PartnershipProject 2” (3GPP2). The techniques described herein may be used for thesystems and radio technologies mentioned above as well as other systemsand radio technologies, including cellular (e.g., LTE) communicationsover an unlicensed and/or shared bandwidth. The description above,however, describes an LTE/LTE-A system for purposes of example, and LTEterminology is used in much of the description above, although thetechniques are applicable beyond LTE/LTE-A applications.

The detailed description set forth above in connection with the appendeddrawings describes examples and does not represent the only examplesthat may be implemented or that are within the scope of the claims. Theterms “example” and “exemplary,” when used in this description, mean“serving as an example, instance, or illustration,” and not “preferred”or “advantageous over other examples.” The detailed description includesspecific details for the purpose of providing an understanding of thedescribed techniques. These techniques, however, may be practicedwithout these specific details. In some instances, well-known structuresand apparatuses are shown in block diagram form in order to avoidobscuring the concepts of the described examples.

Information and signals may be represented using any of a variety ofdifferent technologies and techniques. For example, data, instructions,commands, information, signals, bits, symbols, and chips that may bereferenced throughout the above description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof.

The various illustrative blocks and components described in connectionwith the disclosure herein may be implemented or performed with ageneral-purpose processor, a digital signal processor (DSP), an ASIC, anFPGA or other programmable logic device, discrete gate or transistorlogic, discrete hardware components, or any combination thereof designedto perform the functions described herein. A general-purpose processormay be a microprocessor, but in the alternative, the processor may beany conventional processor, controller, microcontroller, or statemachine. A processor may also be implemented as a combination ofcomputing devices, e.g., a combination of a DSP and a microprocessor,multiple microprocessors, one or more microprocessors in conjunctionwith a DSP core, or any other such configuration.

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope and spirit of the disclosure and appended claims. For example,due to the nature of software, functions described above can beimplemented using software executed by a processor, hardware, firmware,hardwiring, or combinations of any of these. Features implementingfunctions may also be physically located at various positions, includingbeing distributed such that portions of functions are implemented atdifferent physical locations. As used herein, including in the claims,the term “and/or,” when used in a list of two or more items, means thatany one of the listed items can be employed by itself, or anycombination of two or more of the listed items can be employed. Forexample, if a composition is described as containing components A, B,and/or C, the composition can contain A alone; B alone; C alone; A and Bin combination; A and C in combination; B and C in combination; or A, B,and C in combination. Also, as used herein, including in the claims,“or” as used in a list of items (for example, a list of items prefacedby a phrase such as “at least one of” or “one or more of”) indicates adisjunctive list such that, for example, a list of “at least one of A,B, or C” means A or B or C or AB or AC or BC or ABC (i.e., A and B andC).

Computer-readable media includes both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. A storage medium may be anyavailable medium that can be accessed by a general purpose or specialpurpose computer. By way of example, and not limitation,computer-readable media can comprise RAM, ROM, EEPROM, flash memory,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code means in the form of instructions or datastructures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, include compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and Blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above are also includedwithin the scope of computer-readable media.

The previous description of the disclosure is provided to enable aperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the scope of thedisclosure. Thus, the disclosure is not to be limited to the examplesand designs described herein but is to be accorded the broadest scopeconsistent with the principles and novel features disclosed herein.

What is claimed is:
 1. A method for device-to-device discovery at a userequipment (UE), comprising: communicating with a serving base stationusing a first frequency in a first frequency band; transmitting, to theserving base station, information associated with performing a discoveryscan procedure on a second frequency in a second frequency band during adiscovery scan interval, the second frequency being different from thefirst frequency; identifying a capability to skip one or more downlinktransmissions from the serving base station during the discovery scaninterval; receiving a response from the serving base station; skipping afirst portion of the one or more downlink transmissions from the servingbase station during the discovery scan interval based at least in parton the received response; and receiving a second portion of the one ormore downlink transmissions from the serving base station during thediscovery scan interval based at least in part on the received response.2. The method of claim 1, further comprising: tuning to the secondfrequency during the discovery scan interval; and skipping the one ormore downlink transmissions from the serving base station during thediscovery scan interval.
 3. The method of claim 1, wherein the responsecomprises permission to skip the at least a portion of the one or moredownlink transmissions from the serving base station during thediscovery scan interval.
 4. The method of claim 1, wherein the responsecomprises a bitmap associated with the one or more downlinktransmissions from the serving base station, the bitmap identifying thefirst portion of the one or more downlink transmissions the UE isallowed to skip and the second portion the one or more downlinktransmissions the UE is not allowed to skip.
 5. The method of claim 1,further comprising: sending timing information associated with thediscovery scan interval to the serving base station.
 6. The method ofclaim 5, wherein the timing information comprises an identification ofone or more sub-frames where the UE skips the one or more downlinktransmissions from the serving base station.
 7. The method of claim 6,further comprising: selecting the one or more sub-frames based on atiming difference between the serving base station and another devicetransmitting the discovery signal associated with the discovery scanprocedure.
 8. The method of claim 6, further comprising: determining atiming parameter associated with tuning to and tuning away from thesecond frequency band; and selecting the one or more sub-frames toaccount for the timing parameter.
 9. The method of claim 1, wherein theserving base station is associated with a first network and thediscovery scan procedure is associated with a second network, the firstnetwork being different from the second network.
 10. The method of claim1, wherein the discovery scan procedure is the device-to-devicediscovery procedure.
 11. An apparatus for device-to-device discovery,comprising: a processor; memory in electronic communication with theprocessor; and instructions stored in the memory, the instructions beingexecutable by the processor to: communicate with a serving base stationusing a first frequency in a first frequency band; transmit, to theserving base station, information associated with performing a discoveryscan procedure on a second frequency in a second frequency band during adiscovery scan interval, the second frequency being different from thefirst frequency; identify a capability to skip one or more downlinktransmissions from the serving base station during the discovery scaninterval; receive a response from the serving base station; skip a firstportion of the one or more downlink transmissions from the serving basestation during the discovery scan interval based at least in part on thereceived response; and receive a second portion of the one or moredownlink transmissions from the serving base station during thediscovery scan interval based at least in part on the received response.12. The apparatus of claim 11, further comprising instructionsexecutable by the processor to: tune to the second frequency during thediscovery scan interval; and skip the one or more downlink transmissionsfrom the serving base station during the discovery scan interval. 13.The apparatus of claim 11, wherein the response comprises permission toskip the at least a portion of the one or more downlink transmissionsfrom the serving base station during the discovery scan interval. 14.The apparatus of claim 11, wherein the response comprises a bitmapassociated with the one or more downlink transmissions from the servingbase station, the bitmap identifying the first portion of the one ormore downlink transmissions the UE is allowed to skip and the secondportion the one or more downlink transmissions the UE is not allowed toskip.
 15. The apparatus of claim 11, further comprising instructionsexecutable by the processor to: send timing information associated withthe discovery scan interval to the serving base station.
 16. Theapparatus of claim 15, wherein the timing information comprises anidentification of one or more sub-frames where the UE skips the one ormore downlink transmissions from the serving base station.
 17. Theapparatus of claim 16, further comprising instructions executable by theprocessor to: select the one or more sub-frames based on a timingdifference between the serving base station and another devicetransmitting the discovery signal associated with the discovery scanprocedure.
 18. The apparatus of claim 16, further comprisinginstructions executable by the processor to: determine a timingparameter associated with tuning to and tuning away from the secondfrequency band; and select the one or more sub-frames to account for thetiming parameter.
 19. The apparatus of claim 11, wherein the servingbase station is associated with a first network and the discovery scanprocedure is associated with a second network, the first network beingdifferent from the second network.
 20. The apparatus of claim 11,wherein the discovery scan procedure is the device-to-device discoveryprocedure.
 21. An apparatus for device-to-device discovery, comprising:means for communicating with a serving base station using a firstfrequency in a first frequency band; means for transmitting, to theserving base station, information associated with performing a discoveryscan procedure on a second frequency in a second frequency band during adiscovery scan interval, the second frequency being different from thefirst frequency; means for identifying a capability to skip one or moredownlink transmissions from the serving base station during thediscovery scan interval; means for receiving a response from the servingbase station; means for skipping a first portion of the one or moredownlink transmissions from the serving base station during thediscovery scan interval based at least in part on the received response;and means for receiving a second portion of the one or more downlinktransmissions from the serving base station during the discovery scaninterval based at least in part on the received response.
 22. Theapparatus of claim 21, further comprising: means for tuning to thesecond frequency during the discovery scan interval; and means forskipping the one or more downlink transmissions from the serving basestation during the discovery scan interval.
 23. The apparatus of claim21, wherein the response comprises permission to skip the at least aportion of the one or more downlink transmissions from the serving basestation during the discovery scan interval.
 24. The apparatus of claim21, wherein the response comprises a bitmap associated with the one ormore downlink transmissions from the serving base station, the bitmapidentifying the first portion of the one or more downlink transmissionsthe UE is allowed to skip and the second portion the one or moredownlink transmissions the UE is not allowed to skip.
 25. The apparatusof claim 21, further comprising: means for sending timing informationassociated with the discovery scan interval to the serving base station.26. The apparatus of claim 25, wherein the timing information comprisesan identification of one or more sub-frames where the UE skips the oneor more downlink transmissions from the serving base station.
 27. Theapparatus of claim 26, further comprising: means for selecting the oneor more sub-frames based on a timing difference between the serving basestation and another device transmitting the discovery signal associatedwith the discovery scan procedure.
 28. The apparatus of claim 26,further comprising: means for determining a timing parameter associatedwith tuning to and tuning away from the second frequency band; and meansfor selecting the one or more sub-frames to account for the timingparameter.
 29. The apparatus of claim 21, wherein the serving basestation is associated with a first network and the discovery scanprocedure is associated with a second network, the first network beingdifferent from the second network.
 30. The apparatus of claim 21,wherein the discovery scan procedure is the device-to-device discoveryprocedure.
 31. A non-transitory computer readable medium storing codefor device-to-device discovery, the code comprising instructionsexecutable by a processor to: communicate with a serving base stationusing a first frequency in a first frequency band; transmit, to theserving base station, information associated with performing a discoveryscan procedure on a second frequency in a second frequency band during adiscovery scan interval, the second frequency being different from thefirst frequency; identify a capability to skip one or more downlinktransmissions from the serving base station during the discovery scaninterval; receiving a response from the serving base station; skipping afirst portion of the one or more downlink transmissions from the servingbase station during the discovery scan interval based at least in parton the received response; and receiving a second portion of the one ormore downlink transmissions from the serving base station during thediscovery scan interval based at least in part on the received response.32. The non-transitory computer readable medium of claim 31, furthercomprising instructions executable by the processor to: tune to thesecond frequency during the discovery scan interval; and skip the one ormore downlink transmissions from the serving base station during thediscovery scan interval.